1. Field of the Invention
This invention relates to a brake system for a construction vehicle, and more particularly, one including a parking brake and an emergency brake.
2. Description of the Prior Art
In a conventional brake system of the type to which this invention pertains, a parking brake is automatically actuated when a main switch (start switch) is turned off to stop the operation of an engine, even if a parking switch has been turned on to deactuate the parking brake. If the main switch is, then, turned on to start the engine, the parking brake is automatically deactuated. Therefore, a dangerous accident is likely to result from the erroneous operation of the brake system when the vehicle is parked in a sloping road or place.
The conventional brake system permits the vehicle to run even with the parking brake on. It is, therefore, often the case that the driver of the vehicle does not take the trouble to take off the parking brake, but allows the brake lining to burn.
Moreover, the conventional brake system allows the transmission gear in the vehicle to shift to its neutral position automatically if the emergency brake is actuated. This feature involves the possibility of a serious accident, since it is, for example, likely that the vehicle may be unable to get away for itself if it is brought to an emergency stop on a railroad crossing.